Effect of homogenization treatment on microstructure and hot workability of high strength 7B04 aluminium alloy

The effects of homogenization treatment on microstructure, overburnt temperature and hot rolling plasticity of high strength 7B04 aluminium alloy were investigated. Under the condition of homogenization at 470 °C, the starting melting temperature of the primary eutectics in ingot of non-equilibium solidified 7B04 alloy is 478 °C. Using two-step homogenization processing at ultra-high temperature which comprises heating the ingots to 470 °C at 10 °C/h and holding for 64 h, and then heating to 500 °C at 1 °C/h and holding for 10 h, the ingots of 7B04 aluminium alloy could safely pass the sensitive overburnt zone between 480 °C and 495 °C, and the ordinary burnt phenomena of the ingots between 480 °C and 495 °C does not occur because the excess low-melting point eutectic phases in the as-cast alloy dissolve into the matrix during the two-step homogenization processing. Consequently, the hot rolling plasticity of ingot of 7B04 aluminium alloy is greatly improved.